Cross Connections

Cross connections between water supplies and sources of contamination represent one of the most significant threats to public health in the water supply industry. A cross connection is any physical connection between two separate piping systems, the water supply and another substance of unknown quality. A backflow can occur when the unknown substance flows back into the public water supply as water pressure fluctuates. Backflows jeopardize the community’s quality of water and can cause serious health hazards. All commercial customers are required to install and maintain a backflow device.

The State of Maine requires that all public drinking water suppliers maintain a cross connection control program and devices must be inspected annually.

Specifications and Guidelines

The device(s) shall be installed according to the following guidelines:

Pit installations will not be allowed. The device should be equipped with a relief valve assembly, which under certain conditions may dump large volumes of water. Consequently, adequate drainage should be provided. The installation of a strainer is strongly recommended to protect the disks from unnecessary fouling. A bypass around this device will not be allowed (unless protected by a second device). This device should be installed on the downstream (outlet) side of the meter. This device should be installed according to manufacturer specifications.

Customers are required to have backflow prevention devices inspected annually by a person certified by the New England Water Works Association, American Backflow Prevention Association, or the American Society of Safety Engineers.

New Inspection Procedure

The Portland Water District will send you a letter prior to your inspection due date.

Customers have 60 days to complete an inspection with a certified inspector and make repairs if necessary.

A Backflow Device Test Results Form must be completed within 10 business days of the inspection. A customer may also contact our customer service center and request a form be sent to them if they do not have access to the internet. Failure to provide this information may result in disconnection of the water service to your premises.